In metal-making, for example steelmaking, metal can be produced from iron ore in a blast-furnace and converter or as scrap metal and/or direct reduced iron, melted in an electric arc furnace (EAF). The molten metal may be tapped from the EAF to one or more metallurgical vessels, for example to a ladle and further to a tundish. The molten metal may in this manner undergo suitable treatment, both in respect of obtaining the correct temperature for moulding, and for alloying and/or degassing, prior to the moulding process.
When the molten metal has been treated in the above-described manner, it may be discharged through a submerged entry nozzle (SEN) into a mould, typically an open-base mould. The molten metal partially solidifies in the mould. The solidified metal that exits the base of the mould is further cooled as it passed between a plurality of rollers in a spray-chamber.
As the molten metal is discharged into the mould, undesired turbulent molten metal flow around the meniscus may occur. This flow may lead to slag entrainment due to excessive surface velocity or to surface defects due to surface stagnation or level fluctuations.
In order to control the fluid flow, the mould may be provided with an electromagnetic braker (EMBr). The EMBr comprises a magnetic core arrangement which has a number or teeth, and which magnetic core arrangement extends along the long sides of the mould. The EMBr is beneficially arranged in level with the SEN, i.e. at the upper portion of the mould. A respective coil, sometimes referred to as a partial coil, is wound around each tooth. These coils may be connected to a drive that is arranged to feed the coils with a direct (DC) current. A static magnetic field is thereby created in the molten metal. The static magnetic field acts as a brake for the molten metal. The flow at the upper regions, close to the meniscus of the molten metal, may thereby be controlled. As a result, better surface conditions may be obtained.
The utilisation of an EMBr does however not provide optimal fluid flow control of the molten metal, along the entire cross section of the molten metal, near the meniscus.